Polio Vaccine Problems

FILE - Then U.S. President Bill Clinton and First Lady Hillary Rodham Clinton watch as nurse Dorothy Sellers administers an oral polio vaccine to 20-month-old Danielle Bailey at an Arlington County health clinic in Arlington, Va., Feb. 13, 1993. The oral vaccine is credited with dramatically reducing the number of children paralyzed by polio. For years, global health officials have used an oral vaccine in an attempt to wipe out polio from its last remaining strongholds in countries including Afghanistan, Pakistan and Nigeria. In recent weeks, scientists have found evidence of polio spread within Israel, the U.S. and Britain and genetic analyses show the viruses are not only connected, but that the cases were triggered by viruses linked to the oral vaccine. (AP Photo/Greg Gibson, File)